This invention relates to an irrigation system for sequentially irrigating a plurality of areas and, more particularly, to a flow-controlled irrigation system which automatically stops the flow of water to an area when that area has received a predetermined quantity of water and then redirects the flow of water to another area.
Irrigation systems have been used for many years to provide plants and trees with water at various times during their growing cycle. For example, it has been common practice to provide plants and trees with water by means of irrigation ditches, hoses, sprayers, pipes and other types of apparatus. However, in certain situations, such as in orchards where the terrain is uneven, water will run from the high ground to the low. In such cases, the low lying trees may receive more water than those on higher ground.
In other cases, where the cost of water is relatively high it is desirable to control the amount of water provided for each area and to avoid wasting water by providing additional water to some plants in order to adequately water others or by leaving the water on for too long a period.
The above problems have been overcome to a degree by irrigation systems having a plurality of valves with each valve connected by means of pipes to a pressurized source of water. For example, the Rodieck U.S. Pat. Nos. 3,797,253 and 4,014,361, disclose systems wherein each item to be watered is provided with a well around its base and a separate valve within each of the wells. In such systems, one or more risers may be provided in order to force each valve that has been closed by the water reaching a preselected height in the well to remain closed for as long as there is water pressure applied to the system. Such systems also include means to prevent the flow of water to a second valve until such time that a first area has been provided with a predetermined volume of water.
A more recent development is disclosed in my co-pending application entitled "Irrigation System," Ser. No. 07/457,870, which was filed on Dec. 27, 1989, and which is incorporated herein in its entirety by reference. As disclosed therein, an irrigation system includes one or more valve assemblies which are connected in series to a pressurized source of water. Each valve assembly includes a cylindrical housing, a ball valve, an inlet and two outlets with one outlet generally opposite from the inlet in a lower portion of the housing. The other outlet is disposed in an upper portion of the housing and is adapted to direct water to an area of ground for irrigation. A pit and a float are associated with each valve assembly and arranged so that some of the irrigation water will flow into the pit and raise the float. The float is connected to spring biasing means and when the float reaches a predetermined level, the ball valve will spring upwardly to close the upper outlet and redirect the water to another assembly. Water pressure will then maintain the valve in that position.
A further development or improved system of the aforementioned type is disclosed in my copending patent application, U.S. Ser. No. 07/788,282. That application was filed on Nov. 5, 1991, entitled "Improved Irrigation System" and is incorporated herein in its entirety by reference. In that system, the amount of water to be delivered to a given area is independent of any changes in water pressure. For example, an irrigation system in accordance with that invention includes means for storing a force, such as a compressed spring, which is sufficient to overcome a force against the ball-shaped gate member due to the flow of water. Therefore, when the float reaches a preselected height, the force in the spring is released to thereby direct the flow of water through the second outlet. In such systems, the opening of one outlet and closure of a second is solely dependent on the position of the float, i.e., the water level within a pit.
It has now been found that an improvement on the aforementioned system allows an individual to preselect a quantity of water to be supplied to a given area and to activate the mechanism automatically when that quantity of water passes through a valve.